Reference is made to the following co-pending patent applications:
xe2x80x9cDISPLAY PANEL FOR POWER MACHINExe2x80x9d, Ser. No. 29/103,252, filed Apr. 12, 1999; and xe2x80x9cDISPLAY PANEL FOR POWER MACHINExe2x80x9d, Ser. No. 29/103,256, filed Apr. 12, 1999; and xe2x80x9cDISPLAY PANEL FOR POWER MACHINExe2x80x9d, Ser. No. 29/103,257, filed Apr. 12, 1999.
The present invention generally relates to power machines. More specifically, the present invention relates to a main control computer for use with a power machine.
Power machines, such as skid steer loaders, typically have a frame which supports a cab and a movable lift arm which, in turn, supports a work tool such as a bucket. The movable lift arm is pivotally coupled to the frame of the skid steer loader by power actuators which are commonly hydraulic cylinders. In addition, the tool is coupled to the lift arm by one or more additional power actuators which are also commonly hydraulic cylinders. An operator manipulating the skid steer loader raises and lowers the lift arm, and manipulates the tool, by actuating the hydraulic cylinders coupled to the lift arm, and the hydraulic cylinders coupled to the tool. When the operator causes the hydraulic cylinders coupled to the lift arm to increase in length, the lift arm moves generally vertically upward. Conversely, when the operator causes the hydraulic cylinders coupled to the lift arm to decrease in length, the lift arm moves generally vertically downward. Similarly, the operator can manipulate the tool (e.g., tilt the bucket) by controlling the hydraulic cylinders coupled to the lift arm and the working tool to increase or decrease in length, as desired.
Skid steer loaders also commonly have an engine which drives a hydraulic pump to, in turn, power hydraulic traction motors which power movement of the skid steer loader. The traction motors are commonly coupled to the wheels through a drive mechanism such as a chain drive.
The present invention is directed to a computer-based control system for controlling hydraulic and electromechanical actuators on a power machine, such as a skid steer loader. The computer based control system is configured to implement a number of features to enhance certain operational aspects of the power machine.
In one embodiment, the present invention provides selectable pulse width modulated control of auxiliary hydraulics on the power machine. In accordance with another feature of the present invention, substantially any hydraulic function can be placed in a float or detent position. Similarly, assuming that the power machine is hydraulically capable, a plurality of functions can be placed in the float or detent position.
In accordance with another feature of the present invention, a spool lock control solenoid is provided with modulated control. This allows the spool lock to be unlocked in accordance with a power saving technique.
Another aspect of the present invention allows multiple speed control of the loader. Similarly, a transition between the low and high speed is modulated to accomplish smooth speed transitions.
The present invention also provides a number of features with respect to electric or electronically controlled outputs. For example, the state of the engine is monitored such that the starter will not be activated while the engine is running. In addition, the state of a plurality of relays is monitored for proper operation. Similarly, the electrical configuration of a number of relays is also monitored for proper control.
In accordance with another aspect of the present invention, a hydraulic fan speed is controlled based on a number of criteria. The criteria can include operating parameters of the power machine.
The present invention also provides a password hierarchy and functionality for limiting access to certain functions based on the level of a password possessed by the user. Locking and unlocking functionality is also provided to allow re-starting the power machine without re-entering a password.
Further, one embodiment of the present invention allows upgrading an operator input panel from a key-type ignition input to include a keypad input and display device. The update procedure is substantially automated and precludes downgrades without appropriate authority as evidenced by, for example, knowledge of a high level password.